ignition system



June 21,1938. HENDERSON 2,121,385

IGNITION SYSTEM Original Filed May 19, 1936 Q/OS i I b I 1 404; M4 104 1 4 I 101 7 I04 I 104 INVENTOR Leonard .L Hen, cl er'son ATTORNEYS Patented June 21, 1938 vimireo STATES PAT:ENT1oFFiCE f Renewed May 9,1938

" 6 Claims. (o1.12s--14s) This invention relates to ignition systems such as are used iorignitingthe charges in internal combustion engines.

One object of this invention is" to provide an i ignition system including an ignition coil with double primary windings connected in electrical opposition to each other, and in inductive relationship with a single secondary Winding, to-

gether. with suitable means for timing the distribution of current to the primary 1 windings so that the electrical circuit is completed in one primary winding substantially at the instant the circuit is opened in the other'primary winding,

Another object is to provide an ignition system 15 each other, and arranged in inductiverelationship with a secondary winding, together with timing means whereby the circuit is closed in one primary winding while it is opened in the other primary winding so that the opposed windings" assist in bringing the field flux to zero, thereby intensifying the spark obtained in the secondary; circuit by building up the field fully in opposite directions from the'zero point.

Another object'is to provide an ignition system" employing an ignition coil witha double primary and a single secondary, together with a timing device having .a pair of switch arms operated alternately was to provide for high-speed operation, each switcharm having a condenser; asso ciated therewith for'absorbing the; flux of the coil and reducing sparkingacross the terminals.

In the drawing; Figure 1 is a wiring diagram of one ignition system, according to my invention, and

Figure 2 is a wiring diagram of a modified form of ignition system, according to my'invention.

Referring to the drawing in detail, Figure l shows the ignition system of my invention as containing an ignition coil of special type, generally designated H], a battery or similar source of.

electrical energy, generally designated II, a timing device, generally designated l2, a condenser, generally designated IS, a distributing device, generally designated [4, and spark plugs IS. The ignition coil I0 is provided with a core it having associated therewith a pair of primary windings having an ignition coil with double primary windings connected in electrical opp ositionwith The primary windings IT and It may consist of independent windings or of a single primary winding attached at an intermediate point, such as 26. One terr'ninal of the battery fl is'con nected bythe line 2! to the common point 23 between the two prirnarywindings ll and i3, and the other terminal is connected by the line 28 to the breaker arm terminal 29 of the timer l2. The breaker arm terminal 29 is co'nnected'to the breaker arm 30, as at 3|, by the spring 32 and" carries the contact points 33 and 34, respectively. The contact point 34 is arranged to 'engagean adjustable contact point 35 mounted upon the supporting member 36, which is connected by the linev 31 to the terminal 38, the latter beingcohnected by the line 39 to the line 461, which connects one side of the condenser I 3 to the outer end of the primarywinding E8. The opposite side of the condenser I3 is connected by the line ll to the outer terminal of the primary winding ll. 1 l

Fromthe line 4|" the line 42 runs to the ter rninal 43, from which the spring 44 extends to the breaker arm 45 to which it is connected at 36, The breaker arms and 45 are pivotally mounted upon pivot pins 41 and 48, respectively. The springs 32} and 44 urge thearrns 33 and l5 downwardly in Figure 1, The breaker arm 45 is provided'with a contact point 49, arranged to-engage the contact point 33 upon the breaker arm 30, and to this end the breaker arm 45 is provided with a finger 5Q adapted to engage the'timing cam 5|. The latter is illustratedas a two lobed cam adaptedto be used with a four-cylinder engine. It will be evident, however, that a four lobe cam'might be employed for use with an eight cylinder engine.

In the operation of the system shown in Figure 1 the timing cam 5| is rotated, as by the usual cam shaft of the engine, whereupon the breaker arm 45 is moved up and down by the engagement of its finger 5D with the cam 5i. As the breaker arm 45 rises, its contact point 49 engages the contact point 33 on the breaker arm 30, nd raises the contact point 34 out of engagement with the contact point 35. Accordingly, the current from the battery H, or other source of electrical energy, is caused to cease traversing the primary winding i8 and to begin passing through the primary winding I1.

Each time the circuit is made and broken in this manner a high tension current is induced in the secondary winding l9 and flows along the line 22 to the arm 23 of the distributor l4.

. This arm is rotated in a similar manner to the cam 5|, usually upon the same shaft, and disfingers 85 and 86 attached to the arms.

tributes the high tension current to the various poles 24 of the distributor, from whence the current passes along the lines 25 tothe spark plugs I5 and causes a spark to jump across the terminals, igniting the explosive charge within the cylinders. The condenser l3, which is bridged across the outer ends of the primary windings l1 and I8, serves to absorb the flux of the coil and reduce sparking across the terminals. This condenser also will discharge into the primary coil and boost the effect thereof.

The arrangement of the double primary coils in electrical opposition to each other, and the synchronism of the breaker points 33, 49, 34 and 35 cause the electrical circuit to be completed in one primary circuit at the instant the circuit is opened in the other primary circuit. By this arrangement there is no loss of time in starting to build up the magnetic field in the ignition coil, because the opposed windings assist in bringing the field fiux to zero. The spark obtained is intensified because the secondary electro-motive force is proportional to the field density and rate of change of field flux, whereby the opposed windings not only assist in the field drop, but build up the field in the opposite direction after passing through the zero point. This gives a variation which fluctuates by double the amount of a single primary winding and on opposite sides and polarities of the zero point.

The arrangement shown in Figure 1 is particularly adapted for use with slow and medium speed engines. In extremely high-speed engines the weight and inertia of the moving parts of the timer l2 tend to slow down the action, and the increased tension required in the springs 32 and 44 causes excessive wear. Under such circumstances the arrangement shown in Figure 2 is found to eliminate these disadvantages.

The ignition system of Figure 2 is shown as applied to an eight-cylinder engine. This modified system consists of an ignition coil 68, similar to the coil I8 of Figure 1, and having similar double primary windings 6| and 62, core 63 and a common secondary winding 64. A battery 65 is connected by the line 66 to the meeting point 61 of the two primary windings 6i and 62, the opposite ends of which are connected respectively by the lines 68 and 69 to the terminals 18 and H of the timer l2. Bridged across these terminals are condensers I3 and 14 connected thereto by the lines 15 and 16, and having their opposite lines 11 and 18 meeting in the common point 19 connected to the contact point mounting 88. The remaining terminal of the battery 65 is connected by the line Bl to this meeting point 19.

On the contact point mounting are arranged adjustable contact points 82 and 83, which respectively engage similar fixed contacts 84 and 85 on the ends of the twin breaker arms 86 and 81. The breaker arms 86 and 81 are pivotally mounted upon the pivot pins 88 and 89 and having springs 98 and 9| secured thereto, as at 92 and 83. The opposite ends of these springs are secured to the terminals 10 and H, and urge the breaker arms 86 and 81 toward a four-lobed cam 84, which the arms engage by means of the The secondary winding 64 of the coil 68 is connected to the ground, as at 91, by the line 98, and its opposite terminal is connected by the line 98 to the distributor arm I88 of the distributor IOI,

lines [83 to spark plugs I114. The distributor arm I08 is driven synchronously from the engine, and according to the usual practice is driven from the same shaft as the cam 94.

The operation of the ignition system of Figure 2 is similar in principle to that of Figure 1. The double breaker arms 86 and 81 are arranged relatively to the cam 94 so that one set of contact points, such as 83 and 85, is making contact while the other set, such as 82 and 84, is separated. Thus the two sets of contact points alternately make and break the circuit, including the opposed primary windings 6| and 62, whereupon the current flows through these windings alternately in opposite paths. A high tension current is thus induced in the secondary winding 64, this current varying from a maximum of one polarity, through zero, to a minimum of the opposite polarity so that the high tension current varies from one extreme, through zero, to the opposite extreme. By this principle, as stated in Figure 1, the spark is intensified because the secondary electro-motive force is proportional to the field density and rate of change of the field flux. As before, the condensers 13 and I4 serve to absorb the flux of the coil, reduce sparking across the terminals and intensify the effect by discharging into the primary and thereby boosting it.

In Figure 1 the circuit is shown as applied to a four-cylinder engine, whereas in Figure 2 it is shown applied to an eight-cylinder engine. It will be evident, however, that by obvious variations in the arrangement of the breaker arms and cams and also in the distributor poles, the circuit may be adapted to engines of any number of cylinders.

It will be understood that I desire to comprehend within my invention such modifications as come Within the scope of the claims and the invention.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In an ignition system for engines, an induction coil having a pair of primary windings arranged in electrical opposition to one another and a secondary winding, a source of electrical energy, means for alternately directing said energy to said primary windings, said directing means comprising devices including twin sets of contact points, and means arranged to engage one set of contact points while simultaneously disengaging the other set, and means for distributing the induced current from said secondary winding to said engine.

2. In an ignition system for engines, an induction coil having a pair of primary windings arranged in electrical opposition to one another and a secondary winding, a source of electrical energy, means for alternately directing said energy to said primary windings, said directing means comprising devices including twin sets of contact points, means arranged to engage one set of contact points while simultaneously disengaging the other set, said engaging means being adapted to actuate said contact points at substantially equal successive time intervals, and means for distributing the induced current from said secondary winding to said engine.

3. In an ignition system for engines, an induction coil having a primary winding and. a secondary winding, a source of electrical energy connected to an intermediate point in said primary winding to arrange the twin portions thereof in electrical opposition to one another,

means for alternately closing the circuit in one primary portion while simultaneously opening the circuit in the other primary. portion, and means for distributing the induced current from said secondary winding to said engine.

4. In an ignition system for engines, an induction coil having a pair of primary windings arranged in electrical opposition to one another and a secondary winding, a source of electrical energy, means for alternately directing said energy to said primary windings, means for distributing the induced current from said secondary winding to said engine, said directing means comprising a plurality of pairs of switch points and means for engaging one pair while simultaneously disengaging the other pair, said engaging means being adapted to actuate said contact points at substantially equal successive time intervals.

5. In an ignition system for engines, an induction coil having a pair of primary windings arranged in electrical opposition to one another and a secondary winding, a source of electrical energy connected thereto, a switch in circuit with each primary winding and said source, means operatively responsive to the operation of said engine to alternately close one switch while simultaneously opening the other switch, and means for distributing the induced current from said secondary winding to said engine.

6. In an ignition system for engines, an induction coil having a pair of primary windings arranged in electrical opposition to one another and a secondary winding, a source of electrical energy connected thereto, a switch in circuit with each primary winding and said source, means operatively responsive to the operation of said engine to alternately close one switch while simultaneously opening the other switch, and

means for distributing the induced current from said secondary winding to said engine, said engine-responsive means being operative to close and open said contacts at substantially equal 20 successive time intervals.

LEONARD L. HENDERSON. 

